Abstract Scope |
We investigate whether soft martensite plasticity mechanisms, attributed to lath morphology or substructure boundary sliding along the Habit Plane (HP), can delay/inhibit damage initiation in DP steel. ‘Damage-sensitive’ martensite notches are analyzed with state-of-the-art experimental methods: nanoscale in-situ deformation tracking, alignment to detailed microstructure maps, and categorization for each martensite variant, into HP or out-of-HP slip. Strong plasticity (>70%) is observed in martensite notches, enabled by slip along a favorably oriented HP, whereas damaged notches have unfavorably oriented HPs with limited pre-damage strains (<10%), carried by out-of-HP slip. Additionally, Crystal Plasticity (CP) simulations are performed, employing an enriched CP approach modeling a soft plasticity mechanism on the variants’ HP. The enriched CP simulations show considerably lower stresses in non-damaged and plastically deforming notches, thereby revealing that the soft HP mechanism is key for introducing the high plastic anisotropy leading to inhibition of martensite damage in highly strained martensite notches. |